/*
* INSANE - Interactive Structural Analysis Environment
*
* Copyright (C) 2003-2005
* Universidade Federal de Minas Gerais
* Escola de Engenharia
* Departamento de Engenharia de Estruturas
* 
* Author's email :    insane@dees.ufmg.br
* Author's website :  http://www.dees.ufmg.br/insane
* 
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or any later version.
* 
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
* 
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
package br.ufmg.dees.insane.solution;

import br.ufmg.dees.insane.util.IVector;


/** 
 * A class defining a
 *
 * @author Fuina, Jamile & Pitangueira, Roque
 * @since July 2005
 */
/**
 * @author jamile
 *
 */
public class GeneralizedDisplacementControl implements IteractiveStrategy {    
    private Step step;
    private double loadFactor;
    private double lambda;
    private IVector dx_i;
    private IVector dx_i_1;
    private IVector sumdx;
    private double aux1;
    int q = 1;
    
    public GeneralizedDisplacementControl() {
    } 
    	    
    /**
     * @param loadFactor the displacement adopted to the Displacement Control Strategy
     */
    public GeneralizedDisplacementControl(double loadFactor) {
		this.loadFactor = loadFactor;			
	}  
    
    /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#getPredictor()
     */
    public double getPredictor(){
    	if(q == 1){
    		IVector xp = this.step.getXP();
    		sumdx = new IVector(step.getAssembler().getSizeOfXu()); 
    		dx_i = new IVector(step.getAssembler().getSizeOfXu());
    		dx_i_1 = new IVector(step.getAssembler().getSizeOfXu());
    		dx_i = xp;
    		dx_i_1 = xp;
    		aux1 = xp.dot(xp);
    		lambda = this.loadFactor;
    	}
    	else{
    		IVector xp = this.step.getXP();
    		dx_i_1 = dx_i;
    		dx_i = this.step.getXP();
    		double gsp = aux1 / dx_i_1.dot(xp);
    		lambda = this.loadFactor * Math.sqrt(Math.abs(gsp));
    		if((sumdx.dot(xp))< 0.0) lambda *= -1;	
    	}
    	sumdx.scale(lambda,this.step.getXP());
    	q++;
    	return lambda;			
    }	

    /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#getCorrector()
     */
    public double getCorrector(){
    	IVector unbalancedX = this.step.getUnbalancedX();
    	IVector xp = this.step.getXP();
    	lambda = - dx_i_1.dot(unbalancedX) / dx_i_1.dot(xp);
    	IVector aux2 = new IVector (this.step.getAssembler().getSizeOfXu());
    	IVector aux3 = new IVector (this.step.getAssembler().getSizeOfXu());
    	aux2.scale(lambda,xp);
    	aux3.add(aux2, unbalancedX);
    	sumdx.add(sumdx,aux3);
    	return lambda;
    }
    
    /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#getLoadFactor()
     */
    public double getLoadFactor() {
        return loadFactor;
    }
    
    /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#setLoadFactor(double)
     */
    public void setLoadFactor(double lf){
    	this.loadFactor = lf;
    }
    
    /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#getLambda()
     */
    public double getLambda() {
        return lambda;
    }
    
     /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#setStep(Step)
     */
    public void setStep(Step sp){
    	this.step = sp;
    }
    
    /* (non-Javadoc)
     * @see br.ufmg.dees.insane.solution.IteractiveStrategy#getStep()
     */
    public Step getStep(){
    	return step;
    }

}
